Error Console

The Error Console is deprecated in Firefox, and is now only made available if you set the devtools.errorconsole.enabled preference to true. Use the Web Console instead, for web content, or the Browser Console for chrome content.

The Error Console is a tool available in most Mozilla-based applications that is used for reporting errors in the application chrome and in web pages user opens. It reports JavaScript-related errors and warnings, CSS errors and arbitrary messages from chrome code. In Firefox, the Error Console can be opened from the tools menu or by Ctrl-Shift-J.